Logic Q

[evanescence]

[QUOTE]Originally posted by phylay
So many B-s and one d, and I don't ynderstand nothing from the drawing , je m'enerve vite, lol , even if I don't really had the time to think of it... it was impossible to undersrtand what was to find out ?!

[phylay]

BC/AB = 0,61803398874989484820458683436564.
Amina, thanx for your figure, it's been very helpful. I don't have your drawing skills

Shotokan, is it correct?

[Damya]

Originally posted by Amina-DZ



Need to find the ratio: b/d

b/a = a/c (using the 2 corresponding triangles)

but:
c = 2b+d
a = b+d

b/(b+d) = (b+d)/(2b+d)
2(b^2) + bd = (b+d)^2
b^2 = d^2 + bd
b/d = (b^2 - d^2)/d^2
b/d = (b/d)^2 - 1

I'm turning in circles

you've got the solution Amina, just look to the equation
b/d = (b/d)^2 - 1, if I put b/d = x I'll get : x^2 - x - 1 = 0,
second degree equation the solution is the (nombre d'or).

Damya

[phylay]

[QUOTE]Originally posted by evanescence

Originally posted by phylay
So many B-s and one d, and I don't ynderstand nothing from the drawing , je m'enerve vite, lol , even if I don't really had the time to think of it... it was impossible to undersrtand what was to find out ?!

Take a big breath and reread Shotokan's post

[phylay]

Originally posted by Damya

you've got the solution Amina, just look to the equation
b/d = (b/d)^2 - 1, if I put b/d = x I'll get : x^2 - x - 1 = 0,
second degree equation the solution is the (nombre d'or).

Damya

Correct! I noticed it but didn't remember how to calculate the discriminent (delta = b^2-4ac for ax^2+bx+c). I used angles relations instead to find the same number

[Amina-DZ]

Originally posted by phylay
Amina, thanx for your figure, it's been very helpful. I don't have your drawing skills

Glad I was of some help!! I had started seeing pentagrams, pentagons and triangles everywhere so I stopped thinking about it!

Damya, thanks it makes sense now!

[phylay]

"My grandson is about as many days as my son is weeks, and my grandson is as many months as I am in years. My grandson, my son and I together are 160 years. Can you tell me my age in years?"